Non-inverting amplifier relay system



July 10, 1956 A. BRETTELL, JR 2,754,417

NON-INVERTING AMPLIFIER RELAY SYSTEM Original Filed NOV. 24, 1943 INVENTOR. GEORGE A. BRETTELL 7'TORNEYS United States Patent NON-INVERTING ANIPLIFIER RELAY SYSTEM George A. Brettell, Jr., Newark, N. J., assignor to the United States of America as represented by the Secretary of the Navy Original application November 24, 1943, Serial No. 511,626, now Patent No. 2,668,240, dated February 2, 1954. Divided and this application January 9, 1953, Serial No. 332,127

1 Claim. (Cl. 250-27) This invention relates to a vacuum tube circuit, and more particularly to a vacuum tube circuit in which the grid and plate potentials are in phase.

This is a divisional application of an application of George A. Brettell, Ir., Serial No. 511,626, filed November 24, 1943, Patent No. 2,668,240.

It has long been known to those familiar with the art of vacuum tube circuits that if a circuit could be made in which the grid and plate potentials of a tube contained therein, as for example a triode, were in phase instead of 180 out of phase that many new, unique and desirable results could be obtained.

An object of this invention is to produce a circuit in which the grid and plate potentials of a tube contained therein are in phase instead of 180 out of phase.

An object of this invention is to produce a circuit in which the grid and plate potentials of a tube contained therein are in phase without recourse to operation of non-conventional portions of the characteristic curves of the tube.

An object of this invention is to produce a single stage amplifier Without phase reversal as distinguished from the two cascaded stages required by the prior art; and the resultant difiiculty experienced therein with phase shift due to interstage coupling.

An object of this invention is to produce a multivibrator which utilizes a tube whose grid and plate potentials are in phase.

An object of this invention is to produce a relay circuit which utilizes a tube whose grid and plate potentials are in phase.

Another object of this invention is the provision of a circuit utilizing a tube whose grid and plate potentials are in phase which will be economical to manufacture, reliable in operation and which possesses all of the qualities of ruggedness and dependability in service.

Other objects and features will become apparent upon a careful consideration of the following detailed description when taken together with the accompanying drawing, which is designed for the sole purpose of illustration and not as a definition of the limits of the invention, reference for the latter purpose being had to the appended claim.

In the drawing, the single figure represents a circuit diagram illustrating relay tube action.

In the drawing, A and B are two triodes coupled as cathode loaded amplifier and cathode driven amplifier respectively, R1 is the common cathode resistor, R2 the grid resistor, R3 the plate resistor, R4 the grid leak resistor, C the coupling condenser, X the battery, S the relay and T the input terminal. If an impulse is supplied at terminals T and this pulse is positive, the plate current of tube A is interrupted for a predetermined time, depending primarily on the time constant R4C.

The operation of this relay circuit is similar in action to that of Figure 4a of the above mentioned Patent No. 2,668,240. The present circuit is so arranged that a single pulse of defined duration is generated in response 2,754,417 Patented July 10, 1956 to a triggering pulse on the input circuit. The relay shown at S is to be regarded as representative of some output load. Its presence or absence is not to be regarded as affecting the circuit. It merely serves to translate a change in plate current to some usable type of information.

In the standby condition tube A has etfectively zero bias on it since a small current continues to flow to it through resistor R4. The plate current of tube A is a maximum and is of sufiicient strength so that the drop it occasions across resistor R1 serves to bias tube B beyond cut off.

Suppose that a positive pulse is applied at T. This causes tube B to conduct momentarily and therefore causes the plate potential of B to drop. This drop is, however, instantly communicated to grid A through condenser C thus causing the drop across R1 to decrease and allowing plate current to flow in tube B even without the continued presence of a pulse at T. This self-accelerating action continues and takes grid A well into a cut off region thus extinguishing the plate current in tube A. This quasi-steady state condition continues until the charge on condenser C has leaked off through R; to the point where tube A will start to conduct. The action now accelerates in the other direction until the original conditions are reestablished. It is presumed that the pulse at T has by this time disappeared.

As stated in the beginning of the specification, the primary purpose of this invention is a circuit which does not invert the phase between grid and plate potentials. The application which has been illustrated here is to serve as an example only. The combination proves equally effective in other types of tubes such as pentodes, etc., as will be obvious to those skilled in the art. The concrete examples chosen, i. e. triodes, have been selected partly because they are typical of other types, and part ly because, at the present time, two triodes built into one envelope are readily available commercially.

It will also be noted that this disclosure shows some unique elements in other than the basic circuit, but these novelties follow immediately from the possibilities of the basic circuit, and are shown here merely as illustrations.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claim the invention may be practiced otherwise than as specifically described.

I claim:

A relay circuit operable in response to positive triggering pulses comprising a normally conductive cathode loaded amplifier and a normally non-conductive cathode driven amplifier having a common grounded cathode resistor, each said amplifier having a plate, cathode, and grid, both cathodes being directly tied together and to said resistor, a resistor in the plate circuit of the cathode driven amplifier, a parallel resistance-capacitance network coupling the plate of the cathode driven amplifier to the grid of the cathode loaded amplifier, means including a biasing resistor interconnecting the grounded end of said cathode resistor and the grid of said cathode driven amplifier for directly injecting said triggering pulses to said last named grid to initiate current flow in the cathode driven amplifier and reduction of current flow in said cathode loaded amplifier, said resistance-capacitance network having a predetermined time constant for interrupting the current fiow through said cathode loaded amplifier'for a predetermined period of time following injection of one of said triggering pulses, whereby the capacitor of said network is charged during conduction of said cathode loaded amplifier to the potential across the resistance of said network and is discharged during conduction of said cathode driven amplifier solely through the resistance of said network to time the nonconduction of said cathode loaded amplifier, said grid of the cathode driven amplifier being responsive through said biasing resistor to current reduction of said cathode loaded amplifier whereby transfer of current flow from the cathode loaded amplifier is self-accelerated notwithstanding removal of the triggering pulse, a source of plate potential and a relay coil directly connecting the plate of the cathode loaded amplifier to said source for translating a change in plate current therein to an output signal, said relay coil producing substantially no change in the characteristic operation of the cathode loaded amplifier.

References Cited in the file of this patent UNITED STATES PATENTS White Jan. 2, 1940 Stratton Aug. 1, 1944 Ruhlig Aug. 6, 1946 Lakatos Mar. 30, 1948 FOREIGN PATENTS Great Britain Mar. 31, 1943 

